Method and apparatus for handling state variables for security during handover procedure in wireless communication system

ABSTRACT

The present invention relates to a method of performing a handover procedure by a user equipment (UE) in a wireless communication system. Especially, the method includes the steps of receiving a handover command containing information about at least one COUNT value from a first network; establishing a first Packet Data Convergence Protocol (PDCP) entity associated with a second network while maintaining a second PDCP entity associated with the first network; performing a random access procedure with the second network; and based on a handover failure with the second network being detected, transmitting a message for informing the handover failure to the first network with setting at least one state variable for the first PDCP entity according to the at least one COUNT value.

TECHNICAL FIELD

The present invention relates to a wireless communication system, andmore particularly, to a method for handling state variables for securityduring a handover procedure in a wireless communication system and anapparatus therefor.

BACKGROUND ART

Introduction of new radio communication technologies has led toincreases in the number of user equipments (UEs) to which a base station(BS) provides services in a prescribed resource region, and has also ledto increases in the amount of data and control information that the BStransmits to the UEs. Due to typically limited resources available tothe BS for communication with the UE(s), new techniques are needed bywhich the BS utilizes the limited radio resources to efficientlyreceive/transmit uplink/downlink data and/or uplink/downlink controlinformation. In particular, overcoming delay or latency has become animportant challenge in applications whose performance critically dependson delay/latency

Disclosure of Invention Technical Problem

Accordingly, an object of the present invention is to provide a methodfor handling state variables for security during a handover procedure ina wireless communication system and an apparatus therefor.

Solution to Problem

The object of the present invention can be achieved by the method forperforming a handover procedure by a user equipment (UE) in a wirelesscommunication system, comprising the steps of receiving a handovercommand containing information about at least one COUNT value from afirst network; establishing a first Packet Data Convergence Protocol(PDCP) entity associated with a second network while maintaining asecond PDCP entity associated with the first network; performing arandom access procedure with the second network; and based on a handoverfailure with the second network being detected, transmitting a messagefor informing the handover failure to the first network with setting atleast one state variable for the first PDCP entity according to the atleast one COUNT value.

Further, it is suggested a user equipment (UE) in a wirelesscommunication system, the UE comprising: at least one transceiver; atleast one processor; and at least one computer memory operablyconnectable to the at least one processor and storing instructions that,when executed, cause the at least one processor to perform operationscomprising: receiving a handover command containing information about atleast one COUNT value from a first network; establishing a first PacketData Convergence Protocol (PDCP) entity associated with a second networkwhile maintaining a second PDCP entity associated with the firstnetwork; performing a random access procedure with the second network;and based on a handover failure with the second network being detected,transmitting a message for informing the handover failure to the firstnetwork with setting at least one state variable for the first PDCPentity according to the at least one COUNT value.

Preferably, performing a random access procedure comprises: setting atleast one state variables for the second PDCP entity to the at least onestate variables for the first PDCP entity; and transmitting a radioresource control (RRC) message to the second network with incrementingthe at least one state variable for the second PDCP entity by 1.

Preferably, the at least one state variable comprises at least one ofTX_NEXT indicating a COUNT value of a next PDCP service data unit (SDU)to be transmitted and RX_NEXT indicating the COUNT value of the nextPDCP SDU expected to be received. More preferably, the at least oneCOUNT value comprises a first COUNT value for the TX_NEXT and a secondCOUNT value for the RX_NEXT.

Preferably, the information about at least one COUNT value comprises aspecific value for the handover failure, and setting the at least onestate variable for the first PDCP entity comprises incrementing the atleast one state variable by the specific value.

It will be appreciated by persons skilled in the art that the effectsthat can be achieved through the present invention are not limited towhat has been particularly described hereinabove and other advantages ofthe present invention will be more clearly understood from the followingdetailed description.

Advantageous Effects of Invention

According to the present disclosure, the UE does not use the same COUNTvalue for the security to report the handover failure to the sourcenetwork when the UE detects the handover failure to the target network.With this, the security issue can be resolved.

Effects obtainable from the present invention may be non-limited by theabove mentioned effect. And, other unmentioned effects can be clearlyunderstood from the following description by those having ordinary skillin the technical field to which the present invention pertains.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention:

FIG. 1 illustrates an example of a communication system 1 to whichimplementations of the present disclosure is applied;

FIG. 2 is a block diagram illustrating examples of communication deviceswhich can perform a method according to the present disclosure;

FIG. 3 illustrates another example of a wireless device which canperform implementations of the present invention;

FIG. 4 illustrates an example of protocol stacks in a third generationpartnership project (3GPP) based wireless communication system;

FIG. 5 illustrates an example of a frame structure in a 3GPP basedwireless communication system;

FIG. 6 illustrates a data flow example in the 3GPP new radio (NR)system;

FIG. 7 illustrates an example of PDSCH time domain resource allocationby PDCCH, and an example of PUSCH time resource allocation by PDCCH;

FIG. 8 illustrates an example of physical layer processing at atransmitting side;

FIG. 9 illustrates an example of physical layer processing at areceiving side.

FIG. 10 illustrates operations of the wireless devices based on theimplementations of the present disclosure;

FIG. 11 shows a flow chart for handling state variables for securityaccording to the first embodiment of the present disclosure; and

FIG. 12 shows a flow chart for handling state variables for securityaccording to the second embodiment of the present disclosure.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the exemplary implementations ofthe present disclosure, examples of which are illustrated in theaccompanying drawings. The detailed description, which will be givenbelow with reference to the accompanying drawings, is intended toexplain exemplary implementations of the present disclosure, rather thanto show the only implementations that can be implemented according tothe disclosure. The following detailed description includes specificdetails in order to provide a thorough understanding of the presentdisclosure. However, it will be apparent to those skilled in the artthat the present disclosure may be practiced without such specificdetails.

The following techniques, apparatuses, and systems may be applied to avariety of wireless multiple access systems. Examples of the multipleaccess systems include a code division multiple access (CDMA) system, afrequency division multiple access (FDMA) system, a time divisionmultiple access (TDMA) system, an orthogonal frequency division multipleaccess (OFDMA) system, a single carrier frequency division multipleaccess (SC-FDMA) system, and a multicarrier frequency division multipleaccess (MC-FDMA) system. CDMA may be embodied through radio technologysuch as universal terrestrial radio access (UTRA) or CDMA2000. TDMA maybe embodied through radio technology such as global system for mobilecommunications (GSM), general packet radio service (GPRS), or enhanceddata rates for GSM evolution (EDGE). OFDMA may be embodied through radiotechnology such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or evolved UTRA(E-UTRA). UTRA is a part of a universal mobile telecommunications system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE employsOFDMA in DL and SC-FDMA in UL. LTE-advanced (LTE-A) is an evolvedversion of 3GPP LTE.

For convenience of description, implementations of the presentdisclosure are mainly described in regards to a 3GPP based wirelesscommunication system. However, the technical features of the presentdisclosure are not limited thereto. For example, although the followingdetailed description is given based on a mobile communication systemcorresponding to a 3GPP based wireless communication system, aspects ofthe present disclosure that are not limited to 3GPP based wirelesscommunication system are applicable to other mobile communicationsystems. For terms and technologies which are not specifically describedamong the terms of and technologies employed in the present disclosure,the wireless communication standard documents published before thepresent disclosure may be referenced. For example, the followingdocuments may be referenced.

3GPP LTE

-   -   3GPP TS 36.211: Physical channels and modulation    -   3GPP TS 36.212: Multiplexing and channel coding    -   3GPP TS 36.213: Physical layer procedures    -   3GPP TS 36.214: Physical layer; Measurements    -   3GPP TS 36.300: Overall description    -   3GPP TS 36.304: User Equipment (UE) procedures in idle mode    -   3GPP TS 36.314: Layer 2—Measurements    -   3GPP TS 36.321: Medium Access Control (MAC) protocol    -   3GPP TS 36.322: Radio Link Control (RLC) protocol    -   3GPP TS 36.323: Packet Data Convergence Protocol (PDCP)    -   3GPP TS 36.331: Radio Resource Control (RRC) protocol

3GPP NR (e.g. 5G)

-   -   3GPP TS 38.211: Physical channels and modulation    -   3GPP TS 38.212: Multiplexing and channel coding    -   3GPP TS 38.213: Physical layer procedures for control    -   3GPP TS 38.214: Physical layer procedures for data    -   3GPP TS 38.215: Physical layer measurements    -   3GPP TS 38.300: Overall description    -   3GPP TS 38.304: User Equipment (UE) procedures in idle mode and        in RRC inactive state    -   3GPP TS 38.321: Medium Access Control (MAC) protocol    -   3GPP TS 38.322: Radio Link Control (RLC) protocol    -   3GPP TS 38.323: Packet Data Convergence Protocol (PDCP)    -   3GPP TS 38.331: Radio Resource Control (RRC) protocol    -   3GPP TS 37.324: Service Data Adaptation Protocol (SDAP)    -   3GPP TS 37.340: Multi-connectivity; Overall description

In the present disclosure, a user equipment (UE) may be a fixed ormobile device. Examples of the UE include various devices that transmitand receive user data and/or various kinds of control information to andfrom a base station (BS). In the present disclosure, a BS generallyrefers to a fixed station that performs communication with a UE and/oranother BS, and exchanges various kinds of data and control informationwith the UE and another BS. The BS may be referred to as an advancedbase station (ABS), a node-B (NB), an evolved node-B (eNB), a basetransceiver system (BTS), an access point (AP), a processing server(PS), etc. Especially, a BS of the UMTS is referred to as a NB, a BS ofthe enhanced packet core (EPC)/long term evolution (LTE) system isreferred to as an eNB, and a BS of the new radio (NR) system is referredto as a gNB.

In the present disclosure, a node refers to a point capable oftransmitting/receiving a radio signal through communication with a UE.Various types of BSs may be used as nodes irrespective of the termsthereof. For example, a BS, a node B (NB), an e-node B (eNB), apico-cell eNB (PeNB), a home eNB (HeNB), a relay, a repeater, etc. maybe a node. In addition, the node may not be a BS. For example, the nodemay be a radio remote head (RRH) or a radio remote unit (RRU). The RRHor RRU generally has a lower power level than a power level of a BS.Since the RRH or RRU (hereinafter, RRH/RRU) is generally connected tothe BS through a dedicated line such as an optical cable, cooperativecommunication between RRH/RRU and the BS can be smoothly performed incomparison with cooperative communication between BSs connected by aradio line. At least one antenna is installed per node. The antenna mayinclude a physical antenna or an antenna port or a virtual antenna.

In the present disclosure, the term “cell” may refer to a geographicarea to which one or more nodes provide a communication system, or referto radio resources. A “cell” of a geographic area may be understood ascoverage within which a node can provide service using a carrier and a“cell” as radio resources (e.g. time-frequency resources) is associatedwith bandwidth (BW) which is a frequency range configured by thecarrier. The “cell” associated with the radio resources is defined by acombination of downlink resources and uplink resources, for example, acombination of a downlink (DL) component carrier (CC) and an uplink (UL)CC. The cell may be configured by downlink resources only, or may beconfigured by downlink resources and uplink resources. Since DLcoverage, which is a range within which the node is capable oftransmitting a valid signal, and UL coverage, which is a range withinwhich the node is capable of receiving the valid signal from the UE,depends upon a carrier carrying the signal, the coverage of the node maybe associated with coverage of the “cell” of radio resources used by thenode. Accordingly, the term “cell” may be used to represent servicecoverage of the node sometimes, radio resources at other times, or arange that signals using the radio resources can reach with validstrength at other times.

In the present disclosure, a physical downlink control channel (PDCCH),and a physical downlink shared channel (PDSCH) refer to a set oftime-frequency resources or resource elements (REs) carrying downlinkcontrol information (DCI), and a set of time-frequency resources or REscarrying downlink data, respectively. In addition, a physical uplinkcontrol channel (PUCCH), a physical uplink shared channel (PUSCH) and aphysical random access channel (PRACH) refer to a set of time-frequencyresources or REs carrying uplink control information (UCI), a set oftime-frequency resources or REs carrying uplink data and a set oftime-frequency resources or REs carrying random access signals,respectively.

In carrier aggregation (CA), two or more CCs are aggregated. A UE maysimultaneously receive or transmit on one or multiple CCs depending onits capabilities. CA is supported for both contiguous and non-contiguousCCs. When CA is configured the UE only has one radio resource control(RRC) connection with the network. At RRC connectionestablishment/re-establishment/handover, one serving cell provides thenon-access stratum (NAS) mobility information, and at RRC connectionreestablishment/handover, one serving cell provides the security input.This cell is referred to as the Primary Cell (PCell). The PCell is acell, operating on the primary frequency, in which the UE eitherperforms the initial connection establishment procedure or initiates theconnection re-establishment procedure. Depending on UE capabilities,Secondary Cells (SCells) can be configured to form together with thePCell a set of serving cells. An SCell is a cell providing additionalradio resources on top of Special Cell. The configured set of servingcells for a UE therefore always consists of one PCell and one or moreSCells. In the present disclosure, for dual connectivity (DC) operation,the term “special Cell” refers to the PCell of the master cell group(MCG) or the PSCell of the secondary cell group (SCG), and otherwise theterm Special Cell refers to the PCell. An SpCell supports physicaluplink control channel (PUCCH) transmission and contention-based randomaccess, and is always activated. The MCG is a group of serving cellsassociated with a master node, comprising of the SpCell (PCell) andoptionally one or more SCells. The SCG is the subset of serving cellsassociated with a secondary node, comprising of the PSCell and zero ormore SCells, for a UE configured with DC. For a UE in RRC_CONNECTED notconfigured with CA/DC there is only one serving cell comprising of thePCell. For a UE in RRC_CONNECTED configured with CA/DC the term “servingcells” is used to denote the set of cells comprising of the SpCell(s)and all SCells.

The MCG is a group of serving cells associated with a master BS whichterminates at least S1-MME, and the SCG is a group of serving cellsassociated with a secondary BS that is providing additional radioresources for the UE but is not the master BS. The SCG includes aprimary SCell (PSCell) and optionally one or more SCells. In DC, two MACentities are configured in the UE: one for the MCG and one for the SCG.Each MAC entity is configured by RRC with a serving cell supportingPUCCH transmission and contention based Random Access. In the presentdisclosure, the term SpCell refers to such cell, whereas the term SCellrefers to other serving cells. The term SpCell either refers to thePCell of the MCG or the PSCell of the SCG depending on if the MAC entityis associated to the MCG or the SCG, respectively.

In the present disclosure, monitoring a channel refers to attempting todecode the channel. For example, monitoring a physical downlink controlchannel (PDCCH) refers to attempting to decode PDCCH(s) (or PDCCHcandidates).

In the present disclosure, “C-RNTI” refers to a cell RNTI, “SI-RNTI”refers to a system information RNTI, “P-RNTI” refers to a paging RNTI,“RA-RNTI” refers to a random access RNTI, “SC-RNTI” refers to a singlecell RNTI”, “SL-RNTI” refers to a sidelink RNTI, “SPS C-RNTI” refers toa semi-persistent scheduling C-RNTI, and “CS-RNTI” refers to aconfigured scheduling RNTI.

FIG. 1 illustrates an example of a communication system 1 to whichimplementations of the present disclosure is applied.

Three main requirement categories for 5G include (1) a category ofenhanced mobile broadband (eMBB), (2) a category of massive machine typecommunication (mMTC), and (3) a category of ultra-reliable and lowlatency communications (URLLC).

Partial use cases may require a plurality of categories for optimizationand other use cases may focus only upon one key performance indicator(KPI). 5G supports such various use cases using a flexible and reliablemethod.

eMBB far surpasses basic mobile Internet access and covers abundantbi-directional work and media and entertainment applications in cloudand augmented reality. Data is one of 5G core motive forces and, in a 5Gera, a dedicated voice service may not be provided for the first time.In 5G, it is expected that voice will be simply processed as anapplication program using data connection provided by a communicationsystem. Main causes for increased traffic volume are due to an increasein the size of content and an increase in the number of applicationsrequiring high data transmission rate. A streaming service (of audio andvideo), conversational video, and mobile Internet access will be morewidely used as more devices are connected to the Internet. These manyapplication programs require connectivity of an always turned-on statein order to push real-time information and alarm for users. Cloudstorage and applications are rapidly increasing in a mobilecommunication platform and may be applied to both work andentertainment. The cloud storage is a special use case which acceleratesgrowth of uplink data transmission rate. 5G is also used for remote workof cloud. When a tactile interface is used, 5G demands much lowerend-to-end latency to maintain user good experience. Entertainment, forexample, cloud gaming and video streaming, is another core element whichincreases demand for mobile broadband capability. Entertainment isessential for a smartphone and a tablet in any place including highmobility environments such as a train, a vehicle, and an airplane. Otheruse cases are augmented reality for entertainment and informationsearch. In this case, the augmented reality requires very low latencyand instantaneous data volume.

In addition, one of the most expected 5G use cases relates a functioncapable of smoothly connecting embedded sensors in all fields, i.e.,mMTC. It is expected that the number of potential IoT devices will reach204 hundred million up to the year of 2020. An industrial IoT is one ofcategories of performing a main role enabling a smart city, assettracking, smart utility, agriculture, and security infrastructurethrough 5G.

URLLC includes a new service that will change industry through remotecontrol of main infrastructure and an ultra-reliable/availablelow-latency link such as a self-driving vehicle. A level of reliabilityand latency is essential to control a smart grid, automatize industry,achieve robotics, and control and adjust a drone.

5G is a means of providing streaming evaluated as a few hundred megabitsper second to gigabits per second and may complement fiber-to-the-home(FTTH) and cable-based broadband (or DOCSIS). Such fast speed is neededto deliver TV in resolution of 4K or more (6K, 8K, and more), as well asvirtual reality and augmented reality. Virtual reality (VR) andaugmented reality (AR) applications include almost immersive sportsgames. A specific application program may require a special networkconfiguration. For example, for VR games, gaming companies need toincorporate a core server into an edge network server of a networkoperator in order to minimize latency.

Automotive is expected to be a new important motivated force in 5Gtogether with many use cases for mobile communication for vehicles. Forexample, entertainment for passengers requires high simultaneouscapacity and mobile broadband with high mobility. This is because futureusers continue to expect connection of high quality regardless of theirlocations and speeds. Another use case of an automotive field is an ARdashboard. The AR dashboard causes a driver to identify an object in thedark in addition to an object seen from a front window and displays adistance from the object and a movement of the object by overlappinginformation talking to the driver. In the future, a wireless moduleenables communication between vehicles, information exchange between avehicle and supporting infrastructure, and information exchange betweena vehicle and other connected devices (e.g., devices accompanied by apedestrian). A safety system guides alternative courses of a behavior sothat a driver may drive more safely drive, thereby lowering the dangerof an accident. The next stage will be a remotely controlled orself-driven vehicle. This requires very high reliability and very fastcommunication between different self-driven vehicles and between avehicle and infrastructure. In the future, a self-driven vehicle willperform all driving activities and a driver will focus only uponabnormal traffic that the vehicle cannot identify. Technicalrequirements of a self-driven vehicle demand ultra-low latency andultra-high reliability so that traffic safety is increased to a levelthat cannot be achieved by human being.

A smart city and a smart home/building mentioned as a smart society willbe embedded in a high-density wireless sensor network. A distributednetwork of an intelligent sensor will identify conditions for costs andenergy-efficient maintenance of a city or a home. Similar configurationsmay be performed for respective households. All of temperature sensors,window and heating controllers, burglar alarms, and home appliances arewirelessly connected. Many of these sensors are typically low in datatransmission rate, power, and cost. However, real-time HD video may bedemanded by a specific type of device to perform monitoring.

Consumption and distribution of energy including heat or gas isdistributed at a higher level so that automated control of thedistribution sensor network is demanded. The smart grid collectsinformation and connects the sensors to each other using digitalinformation and communication technology so as to act according to thecollected information. Since this information may include behaviors of asupply company and a consumer, the smart grid may improve distributionof fuels such as electricity by a method having efficiency, reliability,economic feasibility, production sustainability, and automation. Thesmart grid may also be regarded as another sensor network having lowlatency.

Mission critical application (e.g. e-health) is one of 5G use scenarios.A health part contains many application programs capable of enjoyingbenefit of mobile communication. A communication system may supportremote treatment that provides clinical treatment in a faraway place.Remote treatment may aid in reducing a barrier against distance andimprove access to medical services that cannot be continuously availablein a faraway rural area. Remote treatment is also used to performimportant treatment and save lives in an emergency situation. Thewireless sensor network based on mobile communication may provide remotemonitoring and sensors for parameters such as heart rate and bloodpressure.

Wireless and mobile communication gradually becomes important in thefield of an industrial application. Wiring is high in installation andmaintenance cost. Therefore, a possibility of replacing a cable withreconstructible wireless links is an attractive opportunity in manyindustrial fields. However, in order to achieve this replacement, it isnecessary for wireless connection to be established with latency,reliability, and capacity similar to those of the cable and managementof wireless connection needs to be simplified. Low latency and a verylow error probability are new requirements when connection to 5G isneeded.

Logistics and freight tracking are important use cases for mobilecommunication that enables inventory and package tracking anywhere usinga location-based information system. The use cases of logistics andfreight typically demand low data rate but require location informationwith a wide range and reliability.

Referring to FIG. 1 , the communication system 1 includes wirelessdevices, base stations (BSs), and a network. Although FIG. 1 illustratesa 5G network as an example of the network of the communication system 1,the implementations of the present disclosure are not limited to the 5Gsystem, and can be applied to the future communication system beyond the5G system.

The BSs and the network may be implemented as wireless devices and aspecific wireless device 200 a may operate as a BS/network node withrespect to other wireless devices.

The wireless devices represent devices performing communication usingradio access technology (RAT) (e.g., 5G New RAT (NR)) or Long-TermEvolution (LTE)) and may be referred to as communication/radio/5Gdevices. The wireless devices may include, without being limited to, arobot 100 a, vehicles 100 b-1 and 100 b-2, an eXtended Reality (XR)device 100 c, a hand-held device 100 d, a home appliance 100 e, anInternet of Things (IoT) device 100 f, and an Artificial Intelligence(AI) device/server 400. For example, the vehicles may include a vehiclehaving a wireless communication function, an autonomous driving vehicle,and a vehicle capable of performing communication between vehicles. Thevehicles may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone).The XR device may include an Augmented Reality (AR)/Virtual Reality(VR)/Mixed Reality (MR) device and may be implemented in the form of aHead-Mounted Device (HMD), a Head-Up Display (HUD) mounted in a vehicle,a television, a smartphone, a computer, a wearable device, a homeappliance device, a digital signage, a vehicle, a robot, etc. Thehand-held device may include a smartphone, a smartpad, a wearable device(e.g., a smartwatch or a smartglasses), and a computer (e.g., anotebook). The home appliance may include a TV, a refrigerator, and awashing machine. The IoT device may include a sensor and a smartmeter.

In the present disclosure, the wireless devices 100 a to 100 f may becalled user equipments (UEs). A user equipment (UE) may include, forexample, a cellular phone, a smartphone, a laptop computer, a digitalbroadcast terminal, a personal digital assistant (PDA), a portablemultimedia player (PMP), a navigation system, a slate personal computer(PC), a tablet PC, an ultrabook, a vehicle, a vehicle having anautonomous traveling function, a connected car, an unmanned aerialvehicle (UAV), an artificial intelligence (AI) module, a robot, anaugmented reality (AR) device, a virtual reality (VR) device, a mixedreality (MR) device, a hologram device, a public safety device, an MTCdevice, an IoT device, a medical device, a FinTech device (or afinancial device), a security device, a weather/environment device, adevice related to a 5G service, or a device related to a fourthindustrial revolution field. The unmanned aerial vehicle (UAV) may be,for example, an aircraft aviated by a wireless control signal without ahuman being onboard. The VR device may include, for example, a devicefor implementing an object or a background of the virtual world. The ARdevice may include, for example, a device implemented by connecting anobject or a background of the virtual world to an object or a backgroundof the real world. The MR device may include, for example, a deviceimplemented by merging an object or a background of the virtual worldinto an object or a background of the real world. The hologram devicemay include, for example, a device for implementing a stereoscopic imageof 360 degrees by recording and reproducing stereoscopic information,using an interference phenomenon of light generated when two laserlights called holography meet. The public safety device may include, forexample, an image relay device or an image device that is wearable onthe body of a user. The MTC device and the IoT device may be, forexample, devices that do not require direct human intervention ormanipulation. For example, the MTC device and the IoT device may includesmartmeters, vending machines, thermometers, smartbulbs, door locks, orvarious sensors. The medical device may be, for example, a device usedfor the purpose of diagnosing, treating, relieving, curing, orpreventing disease. For example, the medical device may be a device usedfor the purpose of diagnosing, treating, relieving, or correcting injuryor impairment. For example, the medical device may be a device used forthe purpose of inspecting, replacing, or modifying a structure or afunction. For example, the medical device may be a device used for thepurpose of adjusting pregnancy. For example, the medical device mayinclude a device for treatment, a device for operation, a device for (invitro) diagnosis, a hearing aid, or a device for procedure. The securitydevice may be, for example, a device installed to prevent a danger thatmay arise and to maintain safety. For example, the security device maybe a camera, a CCTV, a recorder, or a black box. The FinTech device maybe, for example, a device capable of providing a financial service suchas mobile payment. For example, the FinTech device may include a paymentdevice or a point of sales (POS) system. The weather/environment devicemay include, for example, a device for monitoring or predicting aweather/environment.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR)network, and a beyond-5G network. Although the wireless devices 100 a to100 f may communicate with each other through the BSs 200/network 300,the wireless devices 100 a to 100 f may perform direct communication(e.g., sidelink communication) with each other without passing throughthe BSs/network. For example, the vehicles 100 b-1 and 100 b-2 mayperform direct communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a and 150 b may be establishedbetween the wireless devices 100 a to 100 f/BS 200-BS 200. Herein, thewireless communication/connections may be established through variousRATs (e.g., 5G NR) such as uplink/downlink communication 150 a andsidelink communication 150 b (or D2D communication). The wirelessdevices and the BSs/the wireless devices may transmit/receive radiosignals to/from each other through the wirelesscommunication/connections 150 a and 150 b. For example, the wirelesscommunication/connections 150 a and 150 b may transmit/receive signalsthrough various physical channels. To this end, at least a part ofvarious configuration information configuring processes, various signalprocessing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 2 is a block diagram illustrating examples of communication deviceswhich can perform a method according to the present disclosure.

Referring to FIG. 2 , a first wireless device 100 and a second wirelessdevice 200 may transmit/receive radio signals to/from an external devicethrough a variety of RATs (e.g., LTE and NR). In FIG. 2 , {the firstwireless device 100 and the second wireless device 200} may correspondto {the wireless device 100 a to 100 f and the BS 200} and/or {thewireless device 100 a to 100 f and the wireless device 100 a to 100 f}of FIG. 1 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the functions, procedures, and/or methodsdescribed in the present disclosure. For example, the processor(s) 102may process information within the memory(s) 104 to generate firstinformation/signals and then transmit radio signals including the firstinformation/signals through the transceiver(s) 106. The processor(s) 102may receive radio signals including second information/signals throughthe transceiver 106 and then store information obtained by processingthe second information/signals in the memory(s) 104. The memory(s) 104may be connected to the processor(s) 102 and may store a variety ofinformation related to operations of the processor(s) 102. For example,the memory(s) 104 may store software code including commands forperforming a part or the entirety of processes controlled by theprocessor(s) 102 or for performing the procedures and/or methodsdescribed in the present disclosure. Herein, the processor(s) 102 andthe memory(s) 104 may be a part of a communication modem/circuit/chipdesigned to implement RAT (e.g., LTE or NR). The transceiver(s) 106 maybe connected to the processor(s) 102 and transmit and/or receive radiosignals through one or more antennas 108. Each of the transceiver(s) 106may include a transmitter and/or a receiver. The transceiver(s) 106 maybe interchangeably used with radio frequency (RF) unit(s). In thepresent invention, the wireless device may represent a communicationmodem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the functions, procedures, and/or methodsdescribed in the present disclosure. For example, the processor(s) 202may process information within the memory(s) 204 to generate thirdinformation/signals and then transmit radio signals including the thirdinformation/signals through the transceiver(s) 206. The processor(s) 202may receive radio signals including fourth information/signals throughthe transceiver(s) 106 and then store information obtained by processingthe fourth information/signals in the memory(s) 204. The memory(s) 204may be connected to the processor(s) 202 and may store a variety ofinformation related to operations of the processor(s) 202. For example,the memory(s) 204 may store software code including commands forperforming a part or the entirety of processes controlled by theprocessor(s) 202 or for performing the procedures and/or methodsdescribed in the present disclosure. Herein, the processor(s) 202 andthe memory(s) 204 may be a part of a communication modem/circuit/chipdesigned to implement RAT (e.g., LTE or NR). The transceiver(s) 206 maybe connected to the processor(s) 202 and transmit and/or receive radiosignals through one or more antennas 208. Each of the transceiver(s) 206may include a transmitter and/or a receiver. The transceiver(s) 206 maybe interchangeably used with RF unit(s). In the present invention, thewireless device may represent a communication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the functions, procedures, proposals, and/or methodsdisclosed in the present disclosure. The one or more processors 102 and202 may generate messages, control information, data, or informationaccording to the functions, procedures, proposals, and/or methodsdisclosed in the present disclosure. The one or more processors 102 and202 may generate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thefunctions, procedures, proposals, and/or methods disclosed in thepresent disclosure and provide the generated signals to the one or moretransceivers 106 and 206. The one or more processors 102 and 202 mayreceive the signals (e.g., baseband signals) from the one or moretransceivers 106 and 206 and acquire the PDUs, SDUs, messages, controlinformation, data, or information according to the functions,procedures, proposals, and/or methods disclosed in the presentdisclosure.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The functions, procedures, proposals,and/or methods disclosed in the present disclosure may be implementedusing firmware or software and the firmware or software may beconfigured to include the modules, procedures, or functions. Firmware orsoftware configured to perform the functions, procedures, proposals,and/or methods disclosed in the present disclosure may be included inthe one or more processors 102 and 202 or stored in the one or morememories 104 and 204 so as to be driven by the one or more processors102 and 202. The functions, procedures, proposals, and/or methodsdisclosed in the present disclosure may be implemented using firmware orsoftware in the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of the present disclosure, to one or moreother devices. The one or more transceivers 106 and 206 may receive userdata, control information, and/or radio signals/channels, mentioned inthe functions, procedures, proposals, methods, and/or operationalflowcharts disclosed in the present disclosure, from one or more otherdevices. For example, the one or more transceivers 106 and 206 may beconnected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in the functions,procedures, proposals, methods, and/or operational flowcharts disclosedin the present disclosure, through the one or more antennas 108 and 208.In the present disclosure, the one or more antennas may be a pluralityof physical antennas or a plurality of logical antennas (e.g., antennaports). The one or more transceivers 106 and 206 may convert receivedradio signals/channels etc. from RF band signals into baseband signalsin order to process received user data, control information, radiosignals/channels, etc. using the one or more processors 102 and 202. Theone or more transceivers 106 and 206 may convert the user data, controlinformation, radio signals/channels, etc. processed using the one ormore processors 102 and 202 from the base band signals into the RF bandsignals. To this end, the one or more transceivers 106 and 206 mayinclude (analog) oscillators and/or filters. For example, thetransceivers 106 and 206 can up-convert OFDM baseband signals to acarrier frequency by their (analog) oscillators and/or filters under thecontrol of the processors 102 and 202 and transmit the up-converted OFDMsignals at the carrier frequency. The transceivers 106 and 206 mayreceive OFDM signals at a carrier frequency and down-convert the OFDMsignals into OFDM baseband signals by their (analog) oscillators and/orfilters under the control of the transceivers 102 and 202.

In the implementations of the present disclosure, a UE may operate as atransmitting device in uplink (UL) and as a receiving device in downlink(DL). In the implementations of the present disclosure, a BS may operateas a receiving device in UL and as a transmitting device in DL.Hereinafter, for convenience of description, it is mainly assumed thatthe first wireless device 100 acts as the UE, and the second wirelessdevice 200 acts as the BS, unless otherwise mentioned or described. Forexample, the processor(s) 102 connected to, mounted on or launched inthe first wireless device 100 may be configured to perform the UEbehaviour according to an implementation of the present disclosure orcontrol the transceiver(s) 106 to perform the UE behaviour according toan implementation of the present disclosure. The processor(s) 202connected to, mounted on or launched in the second wireless device 200may be configured to perform the BS behaviour according to animplementation of the present disclosure or control the transceiver(s)206 to perform the BS behaviour according to an implementation of thepresent disclosure.

In the present disclosure, at least one memory (e.g. 104 or 204) maystore instructions or programs that, when executed, cause at least oneprocessor, which is operably connected thereto, to perform operationsaccording to some embodiments or implementations of the presentdisclosure.

In the present disclosure, a computer readable storage medium stores atleast one instructions or computer programs that, when executed by atleast one processor, cause the at least one processor to performoperations according to some embodiments or implementations of thepresent disclosure.

In the present disclosure, a processing device or apparatus may compriseat least one processor, and at least one computer memory connectable tothe at least one processor and storing instructions that, when executed,cause the at least one processor to perform operations according to someembodiments or implementations of the present disclosure.

FIG. 3 illustrates another example of a wireless device which canperform implementations of the present invention. The wireless devicemay be implemented in various forms according to a use-case/service(refer to FIG. 1 ).

Referring to FIG. 3 , wireless devices 100 and 200 may correspond to thewireless devices 100 and 200 of FIG. 2 and may be configured by variouselements, components, units/portions, and/or modules. For example, eachof the wireless devices 100 and 200 may include a communication unit110, a control unit 120, a memory unit 130, and additional components140. The communication unit may include a communication circuit 112 andtransceiver(s) 114. For example, the communication circuit 112 mayinclude the one or more processors 102 and 202 of FIG. 2 and/or the oneor more memories 104 and 204 of FIG. 2 . For example, the transceiver(s)114 may include the one or more transceivers 106 and 206 of FIG. 2and/or the one or more antennas 108 and 208 of FIG. 2 . The control unit120 is electrically connected to the communication unit 110, the memory130, and the additional components 140 and controls overall operation ofthe wireless devices. For example, the control unit 120 may control anelectric/mechanical operation of the wireless device based onprograms/code/commands/information stored in the memory unit 130. Thecontrol unit 120 may transmit the information stored in the memory unit130 to the exterior (e.g., other communication devices) via thecommunication unit 110 through a wireless/wired interface or store, inthe memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit (e.g. audio I/O port, video I/O port), a driving unit, and acomputing unit. The wireless device may be implemented in the form of,without being limited to, the robot (100 a of FIG. 1 ), the vehicles(100 b-1 and 100 b-2 of FIG. 1 ), the XR device (100 c of FIG. 1 ), thehand-held device (100 d of FIG. 1 ), the home appliance (100 e of FIG. 1), the IoT device (100 f of FIG. 1 ), a digital broadcast terminal, ahologram device, a public safety device, an MTC device, a medicinedevice, a Fintech device (or a finance device), a security device, aclimate/environment device, the AI server/device (400 of FIG. 1 ), theBSs (200 of FIG. 1 ), a network node, etc. The wireless device may beused in a mobile or fixed place according to a use-example/service.

In FIG. 3 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an electronic control unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a random access memory(RAM), a dynamic RAM (DRAM), a read only memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

FIG. 4 illustrates an example of protocol stacks in a 3GPP basedwireless communication system.

In particular, FIG. 4(a) illustrates an example of a radio interfaceuser plane protocol stack between a UE and a base station (BS) and FIG.4(b) illustrates an example of a radio interface control plane protocolstack between a UE and a BS. The control plane refers to a path throughwhich control messages used to manage call by a UE and a network aretransported. The user plane refers to a path through which datagenerated in an application layer, for example, voice data or Internetpacket data are transported. Referring to FIG. 4(a), the user planeprotocol stack may be divided into a first layer (Layer 1) (i.e., aphysical (PHY) layer) and a second layer (Layer 2). Referring to FIG.4(b), the control plane protocol stack may be divided into Layer 1(i.e., a PHY layer), Layer 2, Layer 3 (e.g., a radio resource control(RRC) layer), and a non-access stratum (NAS) layer. Layer 1, Layer 2 andLayer 3 are referred to as an access stratum (AS).

The NAS control protocol is terminated in an access management function(AMF) on the network side, and performs functions such asauthentication, mobility management, security control and etc.

In the 3GPP LTE system, the layer 2 is split into the followingsublayers: medium access control (MAC), radio link control (RLC), andpacket data convergence protocol (PDCP). In the 3GPP New Radio (NR)system, the layer 2 is split into the following sublayers: MAC, RLC,PDCP and SDAP. The PHY layer offers to the MAC sublayer transportchannels, the MAC sublayer offers to the RLC sublayer logical channels,the RLC sublayer offers to the PDCP sublayer RLC channels, the PDCPsublayer offers to the SDAP sublayer radio bearers. The SDAP sublayeroffers to 5G Core Network quality of service (QoS) flows.

In the 3GPP NR system, the main services and functions of SDAP include:mapping between a QoS flow and a data radio bearer; marking QoS flow ID(QFI) in both DL and UL packets. A single protocol entity of SDAP isconfigured for each individual PDU session.

In the 3GPP NR system, the main services and functions of the RRCsublayer include: broadcast of system information related to AS and NAS;paging initiated by 5G core (5GC) or NG-RAN; establishment, maintenanceand release of an RRC connection between the UE and NG-RAN; securityfunctions including key management; establishment, configuration,maintenance and release of signalling radio bearers (SRBs) and dataradio bearers (DRBs); mobility functions (including: handover andcontext transfer; UE cell selection and reselection and control of cellselection and reselection; Inter-RAT mobility); QoS managementfunctions; UE measurement reporting and control of the reporting;detection of and recovery from radio link failure; NAS message transferto/from NAS from/to UE.

In the 3GPP NR system, the main services and functions of the PDCPsublayer for the user plane include: sequence numbering; headercompression and decompression: ROHC only; transfer of user data;reordering and duplicate detection; in-order delivery; PDCP PDU routing(in case of split bearers); retransmission of PDCP SDUs; ciphering,deciphering and integrity protection; PDCP SDU discard; PDCPre-establishment and data recovery for RLC AM; PDCP status reporting forRLC AM; duplication of PDCP PDUs and duplicate discard indication tolower layers. The main services and functions of the PDCP sublayer forthe control plane include: sequence numbering; ciphering, decipheringand integrity protection; transfer of control plane data; reordering andduplicate detection; in-order delivery; duplication of PDCP PDUs andduplicate discard indication to lower layers.

The RLC sublayer supports three transmission modes: Transparent Mode(TM); Unacknowledged Mode (UM); and Acknowledged Mode (AM). The RLCconfiguration is per logical channel with no dependency on numerologiesand/or transmission durations. In the 3GPP NR system, the main servicesand functions of the RLC sublayer depend on the transmission mode andinclude: Transfer of upper layer PDUs; sequence numbering independent ofthe one in PDCP (UM and AM); error correction through ARQ (AM only);segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs;reassembly of SDU (AM and UM); duplicate detection (AM only); RLC SDUdiscard (AM and UM); RLC re-establishment; protocol error detection (AMonly).

In the 3GPP NR system, the main services and functions of the MACsublayer include: mapping between logical channels and transportchannels; multiplexing/demultiplexing of MAC SDUs belonging to one ordifferent logical channels into/from transport blocks (TB) deliveredto/from the physical layer on transport channels; scheduling informationreporting; error correction through HARQ (one HARQ entity per cell incase of carrier aggregation (CA)); priority handling between UEs bymeans of dynamic scheduling; priority handling between logical channelsof one UE by means of logical channel prioritization; padding. A singleMAC entity may support multiple numerologies, transmission timings andcells. Mapping restrictions in logical channel prioritization controlwhich numerology(ies), cell(s), and transmission timing(s) a logicalchannel can use. Different kinds of data transfer services are offeredby MAC. To accommodate different kinds of data transfer services,multiple types of logical channels are defined i.e. each supportingtransfer of a particular type of information. Each logical channel typeis defined by what type of information is transferred. Logical channelsare classified into two groups: Control Channels and Traffic Channels.Control channels are used for the transfer of control plane informationonly, and traffic channels are used for the transfer of user planeinformation only. Broadcast Control Channel (BCCH) is a downlink logicalchannel for broadcasting system control information, paging ControlChannel (PCCH) is a downlink logical channel that transfers paginginformation, system information change notifications and indications ofongoing PWS broadcasts, Common Control Channel (CCCH) is a logicalchannel for transmitting control information between UEs and network andused for UEs having no RRC connection with the network, and DedicatedControl Channel (DCCH) is a point-to-point bi-directional logicalchannel that transmits dedicated control information between a UE andthe network and used by UEs having an RRC connection. Dedicated TrafficChannel (DTCH) is a point-to-point logical channel, dedicated to one UE,for the transfer of user information. A DTCH can exist in both uplinkand downlink. In Downlink, the following connections between logicalchannels and transport channels exist: BCCH can be mapped to BCH; BCCHcan be mapped to downlink shared channel (DL-SCH); PCCH can be mapped toPCH; CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; andDTCH can be mapped to DL-SCH. In Uplink, the following connectionsbetween logical channels and transport channels exist: CCCH can bemapped to uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH;and DTCH can be mapped to UL-SCH.

FIG. 5 illustrates an example of a frame structure in a 3GPP basedwireless communication system.

The frame structure illustrated in FIG. 5 is purely exemplary and thenumber of subframes, the number of slots, and/or the number of symbolsin a frame may be variously changed. In the 3GPP based wirelesscommunication system, OFDM numerologies (e.g., subcarrier spacing (SCS),transmission time interval (TTI) duration) may be differently configuredbetween a plurality of cells aggregated for one UE. For example, if a UEis configured with different SCSs for cells aggregated for the cell, an(absolute time) duration of a time resource (e.g. a subframe, a slot, ora TTI) including the same number of symbols may be different among theaggregated cells. Herein, symbols may include OFDM symbols (or CP-OFDMsymbols), SC-FDMA symbols (or discrete Fourier transform-spread-OFDM(DFT-s-OFDM) symbols).

Referring to FIG. 5 , downlink and uplink transmissions are organizedinto frames. Each frame has T_(f)=10 ms duration. Each frame is dividedinto two half-frames, where each of the half-frames has 5 ms duration.Each half-frame consists of 5 subframes, where the duration T_(sf) persubframe is 1 ms. Each subframe is divided into slots and the number ofslots in a subframe depends on a subcarrier spacing. Each slot includes14 or 12 OFDM symbols based on a cyclic prefix (CP). In a normal CP,each slot includes 14 OFDM symbols and, in an extended CP, each slotincludes 12 OFDM symbols. The numerology is based on exponentiallyscalable subcarrier spacing Δf=2^(u)*15 kHz. The following table showsthe number of OFDM symbols per slot, the number of slots per frame, andthe number of slots per for the normal CP, according to the subcarrierspacing Δf=2^(u)*15 kHz.

TABLE 1 u N^(slot) _(symb) N^(frame, u) _(slot) N^(subframe, u) _(slot)0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

The following table shows the number of OFDM symbols per slot, thenumber of slots per frame, and the number of slots per for the extendedCP, according to the subcarrier spacing Δf=2^(u)*15 kHz.

TABLE 2 u N^(slot) _(symb) N^(frame, u) _(slot) N^(subframe, u) _(slot)2 12 40 4

A slot includes plural symbols (e.g., 14 or 12 symbols) in the timedomain. For each numerology (e.g. subcarrier spacing) and carrier, aresource grid of N^(size,u) _(grid,x)*N^(RB) _(sc) subcarriers andN^(subframe,u) _(symb) OFDM symbols is defined, starting at commonresource block (CRB) N^(start,u) _(grid) indicated by higher-layersignaling (e.g. radio resource control (RRC) signaling), whereN^(size,u) _(grid,x) is the number of resource blocks in the resourcegrid and the subscript x is DL for downlink and UL for uplink. N^(RB)_(sc) is the number of subcarriers per resource blocks. In the 3GPPbased wireless communication system, N^(RB) _(sc) is 12 generally. Thereis one resource grid for a given antenna port p, subcarrier spacingconfiguration u, and transmission direction (DL or UL). The carrierbandwidth N^(size,u) _(grid) for subcarrier spacing configuration u isgiven by the higher-layer parameter (e.g. RRC parameter). Each elementin the resource grid for the antenna port p and the subcarrier spacingconfiguration u is referred to as a resource element (RE) and onecomplex symbol may be mapped to each RE. Each RE in the resource grid isuniquely identified by an index k in the frequency domain and an index 1representing a symbol location relative to a reference point in the timedomain. In the 3GPP based wireless communication system, a resourceblock is defined by 12 consecutive subcarriers in the frequency domain.

In the 3GPP NR system, resource blocks are classified into CRBs andphysical resource blocks (PRBs). CRBs are numbered from 0 and upwards inthe frequency domain for subcarrier spacing configuration u. The centerof subcarrier 0 of CRB 0 for subcarrier spacing configuration ucoincides with ‘point A’ which serves as a common reference point forresource block grids. In the 3GPP NR system, PRBs are defined within abandwidth part (BWP) and numbered from 0 to N^(sizeBWP,i)−1, where i isthe number of the bandwidth part. The relation between the physicalresource block n_(PRB) in the bandwidth part i and the common resourceblock n_(CRB) is as follows: n_(PRB)=n_(CRB)+N^(size) _(BWP,i), whereN^(size) _(BWP,i) is the common resource block where bandwidth partstarts relative to CRB 0. The BWP includes a plurality of consecutiveresource blocks. A carrier may include a maximum of N (e.g., 5) BWPs. AUE may be configured with one or more BWPs on a given component carrier.Only one BWP among BWPs configured to the UE can active at a time. Theactive BWP defines the UE's operating bandwidth within the cell'soperating bandwidth.

NR frequency bands are defined as 2 types of frequency range, FR1 andFR2. FR2 is may also called millimeter wave(mmW). The frequency rangesin which NR can operate are identified as described in Table 3.

TABLE 3 Frequency Range Corresponding designation frequency rangeSubcarrier Spacing FR1  450 MHz-7125 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

FIG. 6 illustrates a data flow example in the 3GPP NR system.

In FIG. 6 , “RB” denotes a radio bearer, and “H” denotes a header. Radiobearers are categorized into two groups: data radio bearers (DRB) foruser plane data and signalling radio bearers (SRB) for control planedata. The MAC PDU is transmitted/received using radio resources throughthe PHY layer to/from an external device. The MAC PDU arrives to the PHYlayer in the form of a transport block.

In the PHY layer, the uplink transport channels UL-SCH and RACH aremapped to physical uplink shared channel (PUSCH) and physical randomaccess channel (PRACH), respectively, and the downlink transportchannels DL-SCH, BCH and PCH are mapped to physical downlink sharedchannel (PDSCH), physical broad cast channel (PBCH) and PDSCH,respectively. In the PHY layer, uplink control information (UCI) ismapped to PUCCH, and downlink control information (DCI) is mapped toPDCCH. A MAC PDU related to UL-SCH is transmitted by a UE via a PUSCHbased on an UL grant, and a MAC PDU related to DL-SCH is transmitted bya BS via a PDSCH based on a DL assignment.

In order to transmit data unit(s) of the present disclosure on UL-SCH, aUE shall have uplink resources available to the UE. In order to receivedata unit(s) of the present disclosure on DL-SCH, a UE shall havedownlink resources available to the UE. The resource allocation includestime domain resource allocation and frequency domain resourceallocation. In the present disclosure, uplink resource allocation isalso referred to as uplink grant, and downlink resource allocation isalso referred to as downlink assignment. An uplink grant is eitherreceived by the UE dynamically on PDCCH, in a Random Access Response, orconfigured to the UE semi-persistently by RRC. Downlink assignment iseither received by the UE dynamically on the PDCCH, or configured to theUE semi-persistently by RRC signaling from the BS.

In UL, the BS can dynamically allocate resources to UEs via the CellRadio Network Temporary Identifier (C-RNTI) on PDCCH(s). A UE alwaysmonitors the PDCCH(s) in order to find possible grants for uplinktransmission when its downlink reception is enabled (activity governedby discontinuous reception (DRX) when configured). In addition, withConfigured Grants, the BS can allocate uplink resources for the initialHARQ transmissions to UEs. Two types of configured uplink grants aredefined: Type 1 and Type 2. With Type 1, RRC directly provides theconfigured uplink grant (including the periodicity). With Type 2, RRCdefines the periodicity of the configured uplink grant while PDCCHaddressed to Configured Scheduling RNTI (CS-RNTI) can either signal andactivate the configured uplink grant, or deactivate it; i.e. a PDCCHaddressed to CS-RNTI indicates that the uplink grant can be implicitlyreused according to the periodicity defined by RRC, until deactivated.

In DL, the BS can dynamically allocate resources to UEs via the C-RNTIon PDCCH(s). A UE always monitors the PDCCH(s) in order to find possibleassignments when its downlink reception is enabled (activity governed byDRX when configured). In addition, with Semi-Persistent Scheduling(SPS), the BS can allocate downlink resources for the initial HARQtransmissions to UEs: RRC defines the periodicity of the configureddownlink assignments while PDCCH addressed to CS-RNTI can either signaland activate the configured downlink assignment, or deactivate it. Inother words, a PDCCH addressed to CS-RNTI indicates that the downlinkassignment can be implicitly reused according to the periodicity definedby RRC, until deactivated.

<Resource Allocation by PDCCH (i.e. Resource Allocation by DCI)>

PDCCH can be used to schedule DL transmissions on PDSCH and ULtransmissions on PUSCH, where the downlink control information (DCI) onPDCCH includes: downlink assignments containing at least modulation andcoding format (e.g., modulation and coding scheme (MCS) index IMCS),resource allocation, and hybrid-ARQ information related to DL-SCH; oruplink scheduling grants containing at least modulation and codingformat, resource allocation, and hybrid-ARQ information related toUL-SCH. The size and usage of the DCI carried by one PDCCH are varieddepending on DCI formats. For example, in the 3GPP NR system, DCI format0_0 or DCI format 0_1 is used for scheduling of PUSCH in one cell, andDCI format 1_0 or DCI format 1_1 is used for scheduling of PDSCH in onecell.

FIG. 7 illustrates an example of PDSCH time domain resource allocationby PDCCH, and an example of PUSCH time resource allocation by PDCCH.

Downlink control information (DCI) carried by a PDCCH for schedulingPDSCH or PUSCH includes a value m for a row index m+1 to an allocationtable for PDSCH or PUSCH. Either a predefined default PDSCH time domainallocation A, B or C is applied as the allocation table for PDSCH, orRRC configured pdsch-TimeDomainAllocationList is applied as theallocation table for PDSCH. Either a predefined default PUSCH timedomain allocation A is applied as the allocation table for PUSCH, or theRRC configured pusch-TimeDomainAllocationList is applied as theallocation table for PUSCH. Which PDSCH time domain resource allocationconfiguration to apply and which PUSCH time domain resource allocationtable to apply are determined according to a fixed/predefined rule (e.g.Table 5.1.2.1.1-1 in 3GPP TS 38.214 v15.3.0, Table 6.1.2.1.1-1 in 3GPPTS 38.214 v15.3.0).

Each indexed row in PDSCH time domain allocation configurations definesthe slot offset K0, the start and length indicator SLIV, or directly thestart symbol S and the allocation length L, and the PDSCH mapping typeto be assumed in the PDSCH reception. Each indexed row in PUSCH timedomain allocation configurations defines the slot offset K2, the startand length indicator SLIV, or directly the start symbol S and theallocation length L, and the PUSCH mapping type to be assumed in thePUSCH reception. K0 for PDSCH, or K2 for PUSCH is the timing differencebetween a slot with a PDCCH and a slot with PDSCH or PUSCH correspondingto the PDCCH. SLIV is a joint indication of starting symbol S relativeto the start of the slot with PDSCH or PUSCH, and the number L ofconsecutive symbols counting from the symbol S. For PDSCH/PUSCH mappingtype, there are two mapping types: one is Mapping Type A wheredemodulation reference signal (DMRS) is positioned in 3rd or 4th symbolof a slot depending on the RRC signaling, and other one is Mapping TypeB where DMRS is positioned in the first allocated symbol.

The scheduling DCI includes the Frequency domain resource assignmentfield which provides assignment information on resource blocks used forPDSCH or PUSCH. For example, the Frequency domain resource assignmentfield may provide a UE with information on a cell for PDSCH or PUSCHtransmission, information on a bandwidth part for PDSCH or PUSCHtransmission, information on resource blocks for PDSCH or PUSCHtransmission.

<Resource Allocation by RRC>

As mentioned above, in uplink, there are two types of transmissionwithout dynamic grant: configured grant Type 1 where an uplink grant isprovided by RRC, and stored as configured grant; and configured grantType 2 where an uplink grant is provided by PDCCH, and stored or clearedas configured uplink grant based on L1 signaling indicating configureduplink grant activation or deactivation. Type 1 and Type 2 areconfigured by RRC per serving cell and per BWP. Multiple configurationscan be active simultaneously only on different serving cells. For Type2, activation and deactivation are independent among the serving cells.For the same serving cell, the MAC entity is configured with either Type1 or Type 2.

A UE is provided with at least the following parameters via RRCsignaling from a

BS when the configured grant type 1 is configured:

-   -   cs-RNTI which is CS-RNTI for retransmission;    -   periodicity which provides periodicity of the configured grant        Type 1;    -   timeDomainOffset which represents offset of a resource with        respect to SFN=0 in time domain;    -   timeDomainAllocation value m which provides a row index m+1        pointing to an allocation table, indicating a combination of a        start symbol S and length L and PUSCH mapping type;    -   frequencyDomainAllocation which provides frequency domain        resource allocation;

and

-   -   mcsAndTBS which provides IMCS representing the modulation order,        target code rate and transport block size. Upon configuration of        a configured grant Type 1 for a serving cell by RRC, the UE        stores the uplink grant provided by RRC as a configured uplink        grant for the indicated serving cell, and initialise or        re-initialise the configured uplink grant to start in the symbol        according to timeDomainOffset and S (derived from SLIV), and to        reoccur with periodicity. After an uplink grant is configured        for a configured grant Type 1, the UE considers that the uplink        grant recurs associated with each symbol for which:        [(SFN*numberOfSlotsPerFrame (numberOfSymbolsPerSlot)+(slot        number in the frame×numberOfSymbolsPerSlot)+symbol number in the        slot]=(timeDomainOffset numberOfSymbolsPerSlot+S+N*periodicity)        modulo (1024*numberOfSlotsPerFramenumberOfSymbolsPerSlot), for        all N>=0.

A UE is provided with at least the following parameters via RRCsignaling from a

BS when the configured gran Type 2 is configured:

-   -   cs-RNTI which is CS-RNTI for activation, deactivation, and        retransmission; and    -   periodicity which provides periodicity of the configured grant        Type 2. The actual uplink grant is provided to the UE by the        PDCCH (addressed to CS-RNTI). After an uplink grant is        configured for a configured grant Type 2, the UE considers that        the uplink grant recurs associated with each symbol for which:        [(SFN*numberOfSlotsPerFrame*numberOfSymbolsPerSlot)+(slot number        in the frame*numberOfSymbolsPerSlot)+symbol number in the        slot]=[(SFNstart        time*numberOfSlotsPerFrame*numberOfSymbolsPerSlot+slotstart        time*numberOfSymbolsPerSlot+symbol_(start time))+N*periodicity]        modulo (1024×numberOfSlotsPerFrame*numberOfSymbolsPerSlot), for        all N>=0, where SFN_(start time), slot_(start time), and        symbol_(start time) are the SFN, slot, and symbol, respectively,        of the first transmission opportunity of PUSCH where the        configured uplink grant was (re-)initialised.        numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the        number of consecutive slots per frame and the number of        consecutive OFDM symbols per slot, respectively.

For configured uplink grants, the HARQ Process ID associated with thefirst symbol of a UL transmission is derived from the followingequation:

HARQ Process ID=[floor(CURRENT_symbol/periodicity)] modulonrofHARQ-Processes

whereCURRENT_symbol=(SFN×numberOfSlotsPerFrame×numberOfSymbolsPerSlot+slotnumber in the frame×numberOfSymbolsPerSlot+symbol number in the slot),and numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the numberof consecutive slots per frame and the number of consecutive symbols perslot, respectively as specified in TS 38.211. CURRENT_symbol refers tothe symbol index of the first transmission occasion of a repetitionbundle that takes place. A HARQ process is configured for a configureduplink grant if the configured uplink grant is activated and theassociated HARQ process ID is less than nrofHARQ-Processes.

For downlink, a UE may be configured with semi-persistent scheduling(SPS) per serving cell and per BWP by RRC signaling from a BS. Multipleconfigurations can be active simultaneously only on different servingcells. Activation and deactivation of the DL SPS are independent amongthe serving cells. For DL SPS, a DL assignment is provided to the UE byPDCCH, and stored or cleared based on L1 signaling indicating SPSactivation or deactivation. A UE is provided with the followingparameters via RRC signaling from a BS when SPS is configured:

-   -   cs-RNTI which is CS-RNTI for activation, deactivation, and        retransmission;    -   nrofHARQ-Processes: which provides the number of configured HARQ        processes for SPS;    -   periodicity which provides periodicity of configured downlink        assignment for SPS.

When SPS is released by upper layers, all the correspondingconfigurations shall be released.

After a downlink assignment is configured for SPS, the UE considerssequentially that the N^(th) downlink assignment occurs in the slot forwhich: (numberOfSlotsPerFrame*SFN+slot number in theframe)=[(numberOfSlotsPerFrame*SFN_(start time)+slot_(start time))+N*periodicity*numberOfSlotsPerFrame/10]modulo (1024*numberOfSlotsPerFrame), where SFN_(start time) andslot_(start time) are the SFN and slot, respectively, of the firsttransmission of PDSCH where the configured downlink assignment was(re-)initialised.

For configured downlink assignments, the HARQ Process ID associated withthe slot where the DL transmission starts is derived from the followingequation:

HARQ Process ID=[floor(CURRENT_slot×10/(numberOfSlotsPerFrame×periodicity))] modulonrofHARQ-Processes

where CURRENT_slot=[(SFN×numberOfSlotsPerFrame)+slot number in theframe] and numberOfSlotsPerFrame refers to the number of consecutiveslots per frame as specified in TS 38.211.

A UE validates, for scheduling activation or scheduling release, a DLSPS assignment PDCCH or configured UL grant type 2 PDCCH if the cyclicredundancy check (CRC) of a corresponding DCI format is scrambled withCS-RNTI provided by the RRC parameter cs-RNTI and the new data indicatorfield for the enabled transport block is set to 0. Validation of the DCIformat is achieved if all fields for the DCI format are set according toTable 4 or Table 5. Table 4 shows special fields for DL SPS and UL grantType 2 scheduling activation PDCCH validation, and Table 5 shows specialfields for DL SPS and UL grant Type 2 scheduling release PDCCHvalidation.

TABLE 4 DCI format DCI format DCI format 0_0/0_1 1_0 1_1 HARQ processset to all ‘0’s set to all ‘0’s set to all ‘0’s number Redundancy set to‘00’ set to ‘00’ For the enabled version transport block: set to ‘00’

TABLE 5 DCI format DCI format 0_0 1_0 HARQ process number set to all‘0’s set to all ‘0’s Redundancy version set to ‘00’ set to ‘00’Modulation and set to all ‘1’s set to all ‘1’s coding scheme Resourceblock set to all ‘1’s set to all ‘1’s assignment

Actual DL assignment and actual UL grant, and the correspondingmodulation and coding scheme are provided by the resource assignmentfields (e.g. time domain resource assignment field which provides Timedomain resource assignment value m, frequency domain resource assignmentfield which provides the frequency resource block allocation, modulationand coding scheme field) in the DCI format carried by the DL SPS and ULgrant Type 2 scheduling activation PDCCH. If validation is achieved, theUE considers the information in the DCI format as valid activation orvalid release of DL SPS or configured UL grant Type 2.

For UL, the processor(s) 102 of the present disclosure may transmit (orcontrol the transceiver(s) 106 to transmit) the data unit of the presentdisclosure based on the UL grant available to the UE. The processor(s)202 of the present disclosure may receive (or control the transceiver(s)206 to receive) the data unit of the present disclosure based on the ULgrant available to the UE.

For DL, the processor(s) 102 of the present disclosure may receive (orcontrol the transceiver(s) 106 to receive) DL data of the presentdisclosure based on the DL assignment available to the UE. Theprocessor(s) 202 of the present disclosure may transmit (or control thetransceiver(s) 206 to transmit) DL data of the present disclosure basedon the DL assignment available to the UE.

The data unit(s) of the present disclosure is(are) subject to thephysical layer processing at a transmitting side before transmission viaradio interface, and the radio signals carrying the data unit(s) of thepresent disclosure are subject to the physical layer processing at areceiving side. For example, a MAC PDU including the PDCP PDU accordingto the present disclosure may be subject to the physical layerprocessing as follows.

FIG. 8 illustrates an example of physical layer processing at atransmitting side.

The following tables show the mapping of the transport channels (TrCHs)and control information to its corresponding physical channels. Inparticular, Table 6 specifies the mapping of the uplink transportchannels to their corresponding physical channels, Table 7 specifies themapping of the uplink control channel information to its correspondingphysical channel, Table 8 specifies the mapping of the downlinktransport channels to their corresponding physical channels, and Table 9specifies the mapping of the downlink control channel information to itscorresponding physical channel.

TABLE 6 TrCH Physical Channel UL-SCH PUSCH RACH PRACH

TABLE 7 Control information Physical Channel UCI PUCCH, PUSCH

TABLE 8 TrCH Physical Channel DL-SCH PDSCH BCH PBCH PCH PDSCH

TABLE 9 Control information Physical Channel DCI PDCCH

<Encoding>

Data and control streams from/to MAC layer are encoded to offertransport and control services over the radio transmission link in thePHY layer. For example, a transport block from MAC layer is encoded intoa codeword at a transmitting side. Channel coding scheme is acombination of error detection, error correcting, rate matching,interleaving and transport channel or control information mappingonto/splitting from physical channels.

In the 3GPP NR system, following channel coding schemes are used for thedifferent types of TrCH and the different control information types.

TABLE 10 TrCH Coding scheme UL-SCH LDPC DL-SCH PCH BCH Polar code

TABLE 11 Control Information Coding scheme DCI Polar code UCI Block codePolar code

For transmission of a DL transport block (i.e. a DL MAC PDU) or a ULtransport block (i.e. a UL MAC PDU), a transport block CRC sequence isattached to provide error detection for a receiving side. In the 3GPP NRsystem, the communication device uses low density parity check (LDPC)codes in encoding/decoding UL-SCH and DL-SCH. The 3GPP NR systemsupports two LDPC base graphs (i.e. two LDPC base matrixes): LDPC basegraph 1 optimized for small transport blocks and LDPC base graph 2 forlarger transport blocks. Either LDPC base graph 1 or 2 is selected basedon the size of the transport block and coding rate R. The coding rate Ris indicated by the modulation coding scheme (MCS) index IMCS. The MCSindex is dynamically provided to a UE by PDCCH scheduling PUSCH orPDSCH, provided to a UE by PDCCH activating or (re-)initializing the ULconfigured grant 2 or DL SPS, or provided to a UE by RRC signalingrelated to the UL configured grant Type 1. If the CRC attached transportblock is larger than the maximum code block size for the selected LDPCbase graph, the CRC attached transport block may be segmented into codeblocks, and an additional CRC sequence is attached to each code block.The maximum code block sizes for the LDPC base graph 1 and the LDPC basegraph 2 are 8448 bits and 3480 bits, respectively. If the CRC attachedtransport block is not larger than the maximum code block size for theselected LDPC base graph, the CRC attached transport block is encodedwith the selected LDPC base graph. Each code block of the transportblock is encoded with the selected LDPC base graph. The LDPC codedblocks are then individually rat matched. Code block concatenation isperformed to create a codeword for transmission on PDSCH or PUSCH. ForPDSCH, up to 2 codewords (i.e. up to 2 transport blocks) can betransmitted simultaneously on the PDSCH. PUSCH can be used fortransmission of UL-SCH data and layer 1/2 control information. Althoughnot shown in FIG. 8 , the layer 1/2 control information may bemultiplexed with the codeword for UL-SCH data.

<Scrambling and Modulation>

The bits of the codeword are scrambled and modulated to generate a blockof complex-valued modulation symbols.

<Layer Mapping>

The complex-valued modulation symbols of the codeword are mapped to oneor more multiple input multiple output (MIMO) layers. A codeword can bemapped to up to 4 layers. A PDSCH can carry two codewords, and thus aPDSCH can support up to 8-layer transmission. A PUSCH supports a singlecodeword, and thus a PUSCH can support up to 4-layer transmission.

<Transform Precoding>

The DL transmission waveform is conventional OFDM using a cyclic prefix(CP). For DL, transform precoding (in other words, discrete Fouriertransform (DFT)) is not applied.

The UL transmission waveform is conventional OFDM using a CP with atransform precoding function performing DFT spreading that can bedisabled or enabled. In the 3GPP NR system, for UL, the transformprecoding can be optionally applied if enabled. The transform precodingis to spread UL data in a special way to reduce peak-to-average powerratio (PAPR) of the waveform. The transform precoding is a form of DFT.In other words, the 3GPP NR system supports two options for UL waveform:one is CP-OFDM (same as DL waveform) and the other one is DFT-s-OFDM.Whether a UE has to use CP-OFDM or DFT-s-OFDM is configured by a BS viaRRC parameters.

<Subcarrier Mapping>

The layers are mapped to antenna ports. In DL, for the layers to antennaports mapping, a transparent manner (non-codebook based) mapping issupported and how beamforming or MIMO precoding is performed istransparent to the UE. In UL, for the layers to antenna ports mapping,both the non-codebook based mapping and a codebook based mapping aresupported.

For each antenna port (i.e. layer) used for transmission of the physicalchannel (e.g. PDSCH, PUSCH), the complex-valued modulation symbols aremapped to subcarriers in resource blocks allocated to the physicalchannel.

<OFDM Modulation>

The communication device at the transmitting side generates atime-continuous OFDM baseband signal on antenna port p and subcarrierspacing configuration u for OFDM symbol 1 in a TTI for a physicalchannel by adding a cyclic prefix (CP) and performing IFFT. For example,for each OFDM symbol, the communication device at the transmitting sidemay perform inverse fast Fourier transform (IFFT) on the complex-valuedmodulation symbols mapped to resource blocks in the corresponding OFDMsymbol and add a CP to the IFFT-ed signal to generate the OFDM basebandsignal.

<Up-Conversion>

The communication device at the transmitting side up-convers the OFDMbaseband signal for antenna port p, subcarrier spacing configuration uand OFDM symbol 1 to a carrier frequency f0 of a cell to which thephysical channel is assigned.

The processors 102 and 202 in FIG. 2 may be configured to performencoding, schrambling, modulation, layer mapping, transform precoding(for UL), subcarrier mapping, and OFDM modulation. The processors 102and 202 may control the transceivers 106 and 206 connected to theprocessors 102 and 202 to up-convert the OFDM baseband signal onto thecarrier frequency to generate radio frequency (RF) signals. The radiofrequency signals are transmitted through antennas 108 and 208 to anexternal device.

FIG. 9 illustrates an example of physical layer processing at areceiving side.

The physical layer processing at the receiving side is basically theinverse processing of the physical layer processing at the transmittingside.

<Frequency Down-Conversion>

The communication device at a receiving side receives RF signals at acarrier frequency through antennas. The transceivers 106 and 206receiving the RF signals at the carrier frequency down-converts thecarrier frequency of the RF signals into the baseband in order to obtainOFDM baseband signals.

<OFDM Demodulation>

The communication device at the receiving side obtains complex-valuedmodulation symbols via CP detachment and FFT. For example, for each OFDMsymbol, the communication device at the receiving side removes a CP fromthe OFDM baseband signals and performs FFT on the CP-removed OFDMbaseband signals to obtain complex-valued modulation symbols for antennaport p, subcarrier spacing u and OFDM symbol 1.

<Subcarrier Demapping>

The subcarrier demapping is performed on the complex-valued modulationsymbols to obtain complex-valued modulation symbols of a correspondingphysical channel. For example, the processor(s) 102 may obtaincomplex-valued modulation symbols mapped to subcarriers belong to PDSCHfrom among complex-valued modulation symbols received in a bandwidthpart. For another example, the processor(s) 202 may obtaincomplex-valued modulation symbols mapped to subcarriers belong to PUSCHfrom among complex-valued modulation symbols received in a bandwidthpart.

<Transform De-Precoding>

Transform de-precoding (e.g. IDFT) is performed on the complex-valuedmodulation symbols of the uplink physical channel if the transformprecoding has been enabled for the uplink physical channel. For thedownlink physical channel and for the uplink physical channel for whichthe transform precoding has been disabled, the transform de-precoding isnot performed.

<Layer Demapping>

The complex-valued modulation symbols are de-mapped into one or twocodewords.

<Demodulation and Descrambling>

The complex-valued modulation symbols of a codeword are demodulated anddescrambled into bits of the codeword.

<Decoding>

The codeword is decoded into a transport block. For UL-SCH and DL-SCH,either LDPC base graph 1 or 2 is selected based on the size of thetransport block and coding rate R. The codeword may include one ormultiple coded blocks. Each coded block is decoded with the selectedLDPC base graph into a CRC-attached code block or CRC-attached transportblock. If code block segmentation was performed on a CRC-attachedtransport block at the transmitting side, a CRC sequence is removed fromeach of CRC-attached code blocks, whereby code blocks are obtained. Thecode blocks are concatenated into a CRC-attached transport block. Thetransport block CRC sequence is removed from the CRC-attached transportblock, whereby the transport block is obtained. The transport block isdelivered to the MAC layer.

In the above described physical layer processing at the transmitting andreceiving sides, the time and frequency domain resources (e.g. OFDMsymbol, subcarriers, carrier frequency) related to subcarrier mapping,OFDM modulation and frequency up/down conversion can be determined basedon the resource allocation (e.g., UL grant, DL assignment).

For uplink data transmission, the processor(s) 102 of the presentdisclosure may apply (or control the transceiver(s) 106 to apply) theabove described physical layer processing of the transmitting side tothe data unit of the present disclosure to transmit the data unitwirelessly. For downlink data reception, the processor(s) 102 of thepresent disclosure may apply (or control the transceiver(s) 106 toapply) the above described physical layer processing of the receivingside to received radio signals to obtain the data unit of the presentdisclosure.

For downlink data transmission, the processor(s) 202 of the presentdisclosure may apply (or control the transceiver(s) 206 to apply) theabove described physical layer processing of the transmitting side tothe data unit of the present disclosure to transmit the data unitwirelessly. For uplink data reception, the processor(s) 202 of thepresent disclosure may apply (or control the transceiver(s) 206 toapply) the above described physical layer processing of the receivingside to received radio signals to obtain the data unit of the presentdisclosure.

FIG. 10 illustrates operations of the wireless devices based on theimplementations of the present disclosure.

The first wireless device 100 of FIG. 2 may generate firstinformation/signals according to the functions, procedures, and/ormethods described in the present disclosure, and then transmit radiosignals including the first information/signals wirelessly to the secondwireless device 200 of FIG. 2 (S10). The first information/signals mayinclude the data unit(s) (e.g. PDU, SDU, RRC message) of the presentdisclosure. The first wireless device 100 may receive radio signalsincluding second information/signals from the second wireless device 200(S30), and then perform operations based on or according to the secondinformation/signals (S50). The second information/signals may betransmitted by the second wireless device 200 to the first wirelessdevice 100 in response to the first information/signals. The secondinformation/signals may include the data unit(s) (e.g. PDU, SDU, RRCmessage) of the present disclosure. The first information/signals mayinclude contents request information, and the second information/signalsmay include contents specific to the usage of the first wireless device100. Some examples of operations specific to the usages of the wirelessdevices 100 and 200 will be described below.

In some scenarios, the first wireless device 100 may be a hand-helddevice 100 d of FIG. 1 , which performs the functions, procedures,and/or methods described in the present disclosure. The hand-held device100 d may acquire information/signals (e.g., touch, text, voice, images,or video) input by a user, and convert the acquired information/signalsinto the first information/signals. The hand-held devices 100 d maytransmit the first information/signals to the second wireless device 200(S10). The second wireless device 200 may be any one of the wirelessdevices 100 a to 100 f in FIG. 1 or a BS. The hand-held device 100 d mayreceive the second information/signals from the second wireless device200 (S30), and perform operations based on the secondinformation/signals (S50). For example, the hand-held device 100 d mayoutput the contents of the second information/signals to the user (e.g.in the form of text, voice, images, video, or haptic) through the I/Ounit of the hand-held device 100 d.

In some scenarios, the first wireless device 100 may be a vehicle or anautonomous driving vehicle 100 b, which performs the functions,procedures, and/or methods described in the present disclosure. Thevehicle 100 b may transmit (S10) and receive (S30) signals (e.g. dataand control signals) to and from external devices such as othervehicles, BSs (e.g. gNBs and road side units), and servers, through itscommunication unit (e.g. communication unit 110 of FIG. 1C). The vehicle100 b may include a driving unit, and the driving unit may cause thevehicle 100 b to drive on a road. The driving unit of the vehicle 100 bmay include an engine, a motor, a powertrain, a wheel, a brake, asteering device, etc. The vehicle 100 b may include a sensor unit foracquiring a vehicle state, ambient environment information, userinformation, etc. The vehicle 100 b may generate and transmit the firstinformation/signals to the second wireless device 200 (S10). The firstinformation/signals may include vehicle state information, ambientenvironment information, user information, and etc. The vehicle 100 bmay receive the second information/signals from the second wirelessdevice 200 (S30). The second information/signals may include vehiclestate information, ambient environment information, user information,and etc. The vehicle 100 b may drive on a road, stop, or adjust speed,based on the second information/signals (S50). For example, the vehicle100 b may receive map the second information/signals including data,traffic information data, etc. from an external server (S30). Thevehicle 100 b may generate an autonomous driving path and a driving planbased on the second information/signals, and may move along theautonomous driving path according to the driving plan (e.g.,speed/direction control) (S50). For another example, the control unit orprocessor(s) of the vehicle 100 b may generate a virtual object based onthe map information, traffic information, and vehicle positioninformation obtained through a GPS sensor of the vehicle 100 b and anI/O unit 140 of the vehicle 100 b may display the generated virtualobject in a window in the vehicle 100 b (S50).

In some scenarios, the first wireless device 100 may be an XR device 100c of FIG. 1 , which performs the functions, procedures, and/or methodsdescribed in the present disclosure. The XR device 100 c may transmit(S10) and receive (S30) signals (e.g., media data and control signals)to and from external devices such as other wireless devices, hand-helddevices, or media servers, through its communication unit (e.g.communication unit 110 of FIG. 1C). For example, the XR device 100 ctransmits content request information to another device or media server(S10), and download/stream contents such as films or news from anotherdevice or the media server (S30), and generate, output or display an XRobject (e.g. an AR/VR/MR object), based on the secondinformation/signals received wirelessly, through an I/O unit of the XRdevice (S50).

In some scenarios, the first wireless device 100 may be a robot 100 a ofFIG. 1 , which performs the functions, procedures, and/or methodsdescribed in the present disclosure. The robot 100 a may be categorizedinto an industrial robot, a medical robot, a household robot, a militaryrobot, etc., according to a used purpose or field. The robot 100 a maytransmit (S10) and receive (S30) signals (e.g., driving information andcontrol signals) to and from external devices such as other wirelessdevices, other robots, or control servers, through its communicationunit (e.g. communication unit 110 of FIG. 1C). The secondinformation/signals may include driving information and control signalsfor the robot 100 a. The control unit or processor(s) of the robot 100 amay control the movement of the robot 100 a based on the secondinformation/signals.

In some scenarios, the first wireless device 100 may be an AI device 400of FIG. 1 . The AI device may be implemented by a fixed device or amobile device, such as a TV, a projector, a smartphone, a PC, anotebook, a digital broadcast terminal, a tablet PC, a wearable device,a Set Top Box (STB), a radio, a washing machine, a refrigerator, adigital signage, a robot, a vehicle, etc. The AI device 400 may transmit(S10) and receive (S30) wired/radio signals (e.g., sensor information,user input, learning models, or control signals) to and from externaldevices such as other AI devices (e.g., 100 a, . . . , 100 f, 200, or400 of FIG. 1 ) or an AI server (e.g., 400 of FIG. 1 ) usingwired/wireless communication technology. The control unit orprocessor(s) of the AI device 400 may determine at least one feasibleoperation of the AI device 400, based on information which is determinedor generated using a data analysis algorithm or a machine learningalgorithm. The AI device 400 may request that external devices such asother AI devices or AI server provide the AI device 400 with sensorinformation, user input, learning models, control signals and etc.(S10). The AI device 400 may receive second information/signals (e.g.,sensor information, user input, learning models, or control signals)(S30), and the AI device 400 may perform a predicted operation or anoperation determined to be preferred among at least one feasibleoperation based on the second information/signals (S50).

Hereinafter, a transmit operation of a transmitting PDCP entity isdescribed.

At reception of a PDCP SDU from upper layers, the transmitting PDCPentity shall start the discardTimer associated with this PDCP SDU (ifconfigured).

For a PDCP SDU received from upper layers, the transmitting PDCP entityshall:

-   -   associate the COUNT value corresponding to TX_NEXT to this PDCP        SDU (TX_NEXT is a parameter for the transmitting PDCP entity and        indicates the COUNT value of the next PDCP SDU to be        transmitted);    -   perform header compression of the PDCP SDU;    -   perform integrity protection, and ciphering using the TX_NEXT;    -   set the PDCP SN of the PDCP Data PDU to TX_NEXT modulo        2[pdcp-SN-SizeUL];    -   increment TX_NEXT by one; and    -   submit the resulting PDCP Data PDU to lower layer as specified        below.

When submitting a PDCP PDU to lower layer, the transmitting PDCP entityshall submit the PDCP PDU to the associated RLC entity if thetransmitting PDCP entity is associated with one RLC entity.

else, if the transmitting PDCP entity is associated with two RLCentities, if the PDCP duplication is activated and if the PDCP PDU is aPDCP Data PDU, the transmitting PDCP entity shall duplicate the PDCPData PDU and submit the PDCP Data PDU to both associated RLC entities.But, if the PDCP PDU is not the PDCP Data PDU, the transmitting PDCPentity shall submit the PDCP Control PDU to the primary RLC entity.

Further, in case of that the PDCP duplication is not activated, if thetwo associated RLC entities belong to the different Cell Groups; and ifthe total amount of PDCP data volume and RLC data volume pending forinitial transmission in the two associated RLC entities is equal to orlarger than ul-DataSplitThreshold, the transmitting PDCP entity shallsubmit the PDCP PDU to either the primary RLC entity or the secondaryRLC entity. Else, the transmitting PDCP entity shall submit the PDCP PDUto the primary RLC entity.

Meanwhile, in mobility enhancement in NR system, it was agreed that thePDCP entity for SRB1 is established for the source cell and the targetcell. In other words, two PDCP entity having the same radio beareridentifier are established at the same time.

In case of the handover with the security key change, the PDCP entityassociated with the source cell maintains the state variables, and thePDCP entity associated with the target cell sets the state variables tothe initial value, and each PDCP entity has different security key.

The state variables comprise TX_NEXT, RX_NEXT, RX_DELIV and RX_DELIV.

More specifically, as mentioned above, TX_NEXT is a parameter for thetransmitting PDCP entity and indicates the COUNT value of the next PDCPSDU to be transmitted. The initial value is 0.

RX_NEXT, RX_DELIV and RX_DELIV are parameters for the transmitting PDCPentity. Especially, RX_NEXT indicates the COUNT value of the next PDCPSDU expected to be received. The initial value is 0.

Further, RX_DELIV indicates the COUNT value of the first PDCP SDU notdelivered to the upper layers, but still waited for. The initial valueis 0. And, RX_REORD indicates the COUNT value following the COUNT valueassociated with the PDCP Data PDU which triggered t-Reordering.

If the handover failure is detected and the UE falls back to the sourcecell. In this case, the PDCP entity associated with the source cell usesthe maintained state variables to perform the security. That is,integrity and ciphering and the PDCP entity transmits the PDCP PDU tothe peer entity. Therefore, there is no problem to have two PDCPentities for the source cell and the target cell.

In case of the mobility without the security key change, the PDCP entityassociated with the target cell sets the state variables to the statevariables which are used in the PDCP entity associated with source cell,and the PDCP entity associated with the source cell maintains the statevariables, and each PDCP entity has same security key. After that, ifthe RRC message is transmitted via Msg3, the PDCP entity associated withtarget cell performs the security by increment one of the state variable(i.e., TX_NEXT). In this case, if the handover failure is detected andthe UE falls back to the source cell, there is a case where the sameCOUNT value can be used to perform the security and to transmit the RRCmessage to the source and target.

For example, when the UE receives the handover command without securitykey change from the source cell, the UE sets the state variables for thePDCP entity associated with target cell to the state variables used inthe PDCP entity associated with source cell.

In other words, if the TX_NEXT in the PDCP entity associated with sourcecell is 10, the PDCP entity for associated with target cell sets theTX_NEXT to 10. Then, if the UE performs the RACH procedure to the targetcell, the UE may transmit the RRC message secured using TX_NEXT 10 viaMsg3 to the target cell. In this case, the SRB PDCP entity for targetincrements the TX_NEXT (i.e., TX_NEXT 11) to transmit the RRC message tothe target cell. After that, if the UE detects the DAPS HO failure, thePDCP entity associated with source cell performs the security usingTX_NEXT 10 for the RRC message and transmits the RRC message to thesource.

Considering this example, if the DAPS HO failure happens, the UE maytransmit the RRC messages which are secured using the same COUNT value(i.e., TX_NEXT). Thus, there is a requirement that the UE shall not usethe same COUNT value with the same security key to perform the security.

In order not to use the same COUNT value for the security, the networkshould indicate the COUNT value to be used for transmission of thepacket to the source cell when the handover failure is detected.

First Embodiment

According to the first embodiment of the present disclosure, it issuggested that a PDCP entity sets the state variable to a COUNT valueindicated by a network when the handover failure happens. For this, thenetwork should indicate the COUNT value in the handover command.

When a UE receives the handover command (i.e., reconfiguration withsync) containing a COUNT value from a first network, the UE establishesthe PDCP entity associated with for a second network (hereinafter,second PDCP entity) while maintaining the PDCP entity associated withfor the first network (hereinafter, first PDCP entity). In this case,the UE has two PDCP entity having the same radio bearer identifier.

The UE sets state variables for the second PDCP entity to the statevariables used in the first PDCP entity.

For example, if the first PDCP entity maintains the TX_NEXT=100, theRX_DELIV=200, the RX_NEXT=205, and RX_REORD=206, the UE sets the statevariables for the second PDCP entity to the TX_NEXT=100, theRX_DELIV=200, the RX_NEXT=205, and RX_REORD=206.

For the transmission procedure, the TX_NEXT indicates the COUNT value ofthe next PDCP SDU to be transmitted.

For the reception procedure, the RX_NEXT indicates the COUNT value ofthe next PDCP SDU expected to be received. The initial value is 0, andthe RX_DELIV indicates the COUNT value of the first PDCP SDU notdelivered to the upper layers, but still waited for. The initial valueis 0. Further, RX_REORD indicates the COUNT value following the COUNTvalue associated with the PDCP Data PDU which triggered t-Reordering.

The COUNT value is used to set a specific state variable for the firstPDCP entity. For example, the UE sets the COUNT value to the TX_NEXT forthe first PDCP entity upon detecting the handover failure.

Alternatively, the first network can provide more than one COUNT values.In this case, the first network should indicate that each COUNT value ismapped to a particular state variable. For example, if the first networkprovides two COUNT values, the first network provides information onthat the first COUNT value is associated with TX_NEXT and the secondCOUNT value is associated with RX_DELIV.

After establishing the second PDCP entity, the UE tries to make aconnection to the second network by performing the random accessprocedure to the second network while maintaining the connection to thefirst network.

When the UE detects the handover failure, the UE sets the state variablefor the first PDCP entity to the COUNT value configured by the firstnetwork. For example, if the COUNT value=10000 is contained in thehandover command, the UE sets the TX_NEXT to the 10000 upon detectingthe handover failure.

Alternatively, if the first network provides more than one COUNT values,the UE sets each COUNT value to the corresponding state variables. Forexample, the first network provides two COUNT values, the first COUNTvalue=10000 is for the TX_NEXT and the second COUNT value=20000 is forthe RX_DELIV, the UE sets the TX_NEXT for the first PDCP entity to the10000 and the RX_DELIV for the first PDCP entity to the 20000.

Alternatively, the UE can set the state variable(s) for the first PDCPentity when the UE establishes the second PDCP entity.

After detecting the handover failure and setting the state variables forthe first PDCP entity, the UE reports the handover failure to the firstnetwork.

FIG. 11 shows a flow chart for handling state variables for securityaccording to the first embodiment of the present disclosure.

Referring to FIG. 11 , at S1101, the UE receives a handover commandcontaining the COUNT value=10000 from a first network.

At S1102 and S1103, the UE establishes the second PDCP entity whilemaintaining the first PDCP entity and the UE sets the state variablesfor the second PDCP entity to the state variables used in the first PDCPentity.

The UE performs the random access procedure to the second network whilemaintaining the connection with the first network at S1104, but the UEdetects the handover failure on the second network at S1105.

At S1106, the UE sets the state variable, i.e., TX_NEXT, for the firstPDCP entity to the COUNT value=10000.

Finally, at S1107, the UE reports the connection failure to the handovernetwork.

Second Embodiment

According to the second embodiment of the present disclosure, it issuggested that a PDCP entity associated with a first network incrementsa PDCP state variable before transmitting the handover failure to thefirst network.

When the UE receives the handover command containing a specific valuefrom the first network, the UE establishes the second PDCP entity whilemaintaining the first PDCP entity. Preferably, the specific value isused to increment the state variable for the first PDCP entity.

After receiving the handover command from the first network, the UEtries to make a connection to the second network.

When the UE detects the handover failure with the second network, the UEincrements a state variable, i.e., TX_NEXT, for the first PDCP entity bythe specific value.

For example, it is assumed that the TX_NEXT for the first PDCP entity is100 and the specific value is 20. In this case, when the UE detects thehandover failure with the second network, the UE increments the TX_NEXTby 20, i.e., TX_NEXT=120.

Alternatively, the UE increments more than one state variables by thespecific value. For example, the UE can increment the TX_NEXT andRX_DELIV for the first PDCP entity by the specific value.

If the specific value is not contained/configured in the handovercommand, the UE increments one or more state variables for the firstPDCP entity by one even if the UE does not transmit the packet via thefirst PDCP entity.

Alternatively, the UE can update the state variables for the first PDCPentity when the UE establishes the second PDCP entity.

After detecting the handover failure and setting the state variables forthe first PDCP entity, the UE reports the handover failure to the firstnetwork.

FIG. 12 shows a flow chart for handling state variables for securityaccording to the second embodiment of the present disclosure.

Referring to FIG. 12 , at S1201, the UE receives a handover commandcontaining the specific value=20 from a first network.

The UE establishes the second PDCP entity while maintaining the firstPDCP entity at S1202 and the UE sets the state variables for the secondPDCP entity to the state variables used in the first PDCP entity atS1203.

The UE performs the random access procedure to the second network whilemaintaining the connection with the first network at S1204, but detectsthe handover failure on the second network at S1205.

According to the second embodiment of the present disclosure, at S1206,the UE increments the state variable, i.e., TX_NEXT, for the first PDCPentity by 20.

Finally, the UE reports the handover failure to the first network atS1207.

According to the present disclosure, the UE does not use the same COUNTvalue for the security to report the handover failure to the sourcenetwork when the UE detects the handover failure to the target network.With this, the security issue can be resolved.

1. A method for performing a handover procedure by a user equipment (UE)in a wireless communication system, the method comprising: receiving ahandover command containing information about at least one COUNT valuefrom a first network; establishing a first Packet Data ConvergenceProtocol (PDCP) entity associated with a second network whilemaintaining a second PDCP entity associated with the first network;performing a random access procedure with the second network; and basedon a handover failure with the second network being detected,transmitting a message for informing the handover failure to the firstnetwork with setting at least one state variable for the first PDCPentity according to the at least one COUNT value.
 2. The method of claim1, wherein performing a random access procedure comprises: setting atleast one state variables for the second PDCP entity to the at least onestate variables for the first PDCP entity; and transmitting a radioresource control (RRC) message to the second network with incrementingthe at least one state variable for the second PDCP entity by
 1. 3. Themethod of claim 1, wherein the at least one state variable comprises atleast one of TX_NEXT indicating a COUNT value of a next PDCP servicedata unit (SDU) to be transmitted and RX_NEXT indicating the COUNT valueof the next PDCP SDU expected to be received.
 4. The method of claim 3,wherein the at least one COUNT value comprises a first COUNT value forthe TX_NEXT and a second COUNT value for the RX_NEXT.
 5. The method ofclaim 1, wherein the information about at least one COUNT valuecomprises a specific value for the handover failure, and wherein settingthe at least one state variable for the first PDCP entity comprisesincrementing the at least one state variable by the specific value.
 6. Auser equipment (UE) in a wireless communication system, the UEcomprising: at least one transceiver; at least one processor; and atleast one computer memory operably connectable to the at least oneprocessor and storing instructions that, when executed, cause the atleast one processor to perform operations comprising: receiving ahandover command containing information about at least one COUNT valuefrom a first network; establishing a first Packet Data ConvergenceProtocol (PDCP) entity associated with a second network whilemaintaining a second PDCP entity associated with the first network;performing a random access procedure with the second network; and basedon a handover failure with the second network being detected,transmitting a message for informing the handover failure to the firstnetwork with setting at least one state variable for the first PDCPentity according to the at least one COUNT value.
 7. The UE of claim 6,wherein performing a random access procedure comprises: setting at leastone state variables for the second PDCP entity to the at least one statevariables for the first PDCP entity; and transmitting a radio resourcecontrol (RRC) message to the second network with incrementing the atleast one state variable for the second PDCP entity by
 1. 8. The UE ofclaim 6, wherein the at least one state variable comprises at least oneof TX_NEXT indicating a COUNT value of a next PDCP service data unit(SDU) to be transmitted and RX_NEXT indicating the COUNT value of thenext PDCP SDU expected to be received.
 9. The UE of claim 8, wherein theat least one COUNT value comprises a first COUNT value for the TX_NEXTand a second COUNT value for the RX_NEXT.
 10. The UE of claim 6, whereinthe information about at least one COUNT value comprises a specificvalue for the handover failure, and wherein setting the at least onestate variable for the first PDCP entity comprises incrementing the atleast one state variable by the specific value.
 11. An apparatus for auser equipment (UE), the apparatus comprising: at least one processor;and at least one computer memory operably connectable to the at leastone processor and storing instructions that, when executed, cause the atleast one processor to perform operations comprising: receiving ahandover command containing information about at least one COUNT valuefrom a first network; establishing a first Packet Data ConvergenceProtocol (PDCP) entity associated with a second network whilemaintaining a second PDCP entity associated with the first network;performing a random access procedure with the second network; and basedon a handover failure with the second network being detected,transmitting a message for informing the handover failure to the firstnetwork with setting at least one state variable for the first PDCPentity according to the at least one COUNT value.
 12. A computerreadable storage medium storing at least one computer program comprisinginstructions that, when executed by at least one processor, cause the atleast one processor to perform operations for a user equipment (UE), theoperations comprising: receiving a handover command containinginformation about at least one COUNT value from a first network;establishing a first Packet Data Convergence Protocol (PDCP) entityassociated with a second network while maintaining a second PDCP entityassociated with the first network; performing a random access procedurewith the second network; and based on a handover failure with the secondnetwork being detected, transmitting a message for informing thehandover failure to the first network with setting at least one statevariable for the first PDCP entity according to the at least one COUNTvalue.